The Spacelab Life Sciences-2 (SLS-2) mission provided scientists with the unique opportunity of obtaining inflight rodent tissue and blood samples during a 14-day mission flown in October, 1993. In order to successfully obtain these samples, Ames Research Center's Space Life Sciences Payloads Office has developed an innovative, modular approach to packaging the instruments used to obtain and preserve the inflight tissue and blood samples associated with the hematology experiments on SLS-2.The design approach organized the multitude of instruments into 12 different 5x6x1 inch kits which were each used to accomplish a particular experiment functional objective on any given day during the mission. The twelve basic kits included blood processing, isotope and erythropoietin injection, body mass measurement, and microscope slides. Each kit contained all of the syringes, vials, microscope slides, etc. necessary for processing and storing blood and tissue samples for one rat on a particular day. On flight day 6 of the SLS-2 mission, for example, a total of 5 rats had blood samples taken, radioisotope labels injected, and body mass measured. In order to fulfill these experiment functional objectives, the astronaut crewmember removed from the onboard stowage a total of 5 each of the blood processing, radioisotope injection, microscope slide, and mass measurement kits and set them up in the General Purpose Work Station (GPWS). The GPWS is a laminar flow work bench where all of the experimental procedures were carried out. For ease of stowage and transportation the kits were enclosed in larger Zero™ boxes, measuring 9.5x7x6 inches.In support of the SLS-2 mission, a total of 1245 components, packaged into 128 kits and stowed in 17 Zero™ boxes were required to complete the scientific objectives of the hematology experiments. Astronaut crew members spent many hours in training for the mission using these kits and found the overall design to be extremely easy to use and laid out in a logical, simple configuration which minimizes chances for error during the complex, tedious procedures inflight. This paper also summarizes inflight performance of the kits on SLS-2.The SLS-2 mission was the second in a series of dedicated life sciences Spacelab missions, and as such was furthering the important research initiated on SLS-1 in June, 1991. The payload was comprised of 14 different experiments, 6 using animals (rats) as subjects and 8 using the crew as subjects.The six animal experiments on SLS-2 were grouped into four scientific disciplines- hematology (two experiments), bone, muscle (two experiments), and vestibular. Each of the six experiments were assigned a certain number of the total of 48 rats flown onboard, constituting their respective flight groups. The two hematology experiments shared a total of 15 animals, which were subdivided into three groups of 5, simply denoted as A, B, and C.